Chapter 3:Enthalpy Measurements of Condensed Matter by Peltier-element-based Adiabatic Scanning Calorimetry (pASC)
Chapter 3:Enthalpy Measurements of Condensed Matter by Peltier-element-based Adiabatic Scanning Calorimetry (pASC)
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第 3 章：基于珀耳帖元件的绝热扫描量热法 (pASC) 测量凝聚态物质的焓
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发表时间：
2017
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通讯作者：
T. Letcher
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作者：
J. Thoen;J. Leys;P. L. Perez;C. Glorieux;E. Wilhelm;T. Letcher
绝热扫描量热法(ASC)是一种同时测量液体或固体凝聚体样品的热容和热容随温度变化的技术。ASC的基本概念在于将恒定的加热或冷却功率施加到包含要研究的材料的样品盒上。虽然ASC概念在1970年代末首次实施，并在多年来得到进一步改进，但仪器在很大程度上仍然限于具体的研究应用，因为它们需要熟练和训练有素的人员进行操作。这不仅仅是因为为了施加绝热条件而精心设计的结构和控制，以及复杂的样品池安装。在这一章中，我们描述了一种新的实现方式，在样品池和绝热屏蔽层之间加入了一个珀尔蒂埃单元。新型用户友好的基于Peltier元件的绝热扫描量热仪(PASC)允许在大温度范围内对毫克大小的样品进行测量，并具有高分辨率的温度、热和热容。除了PASC的加热和冷却模式外，它还可以用作经典的热步进量热计和差示扫描量热仪(DSC)类型的热流或功率补偿模式。作为例子，给出了镓和水的熔融转变，以及水脂泡悬浮液和液晶中的相变的焓结果。
Adiabatic scanning calorimetry (ASC) is a technique that aims to simultaneously measure the temperature dependence of the enthalpy and the heat capacity of a liquid or solid condensed matter sample. The basic concept of ASC resides in applying a constant heating or cooling power to a sample holder containing the material to study. Although the ASC concept was first implemented in the late 1970s and further improved over the years, instruments remained largely limited to specific research applications because they required operation by skilled and trained personnel. This was not least due to elaborate construction and control to impose adiabatic conditions, as well as complicated sample cell mounting. In this chapter we describe a novel implementation, incorporating a Peltier element between the sample cell and the adiabatic shield. The new user-friendly Peltier-element-based adiabatic scanning calorimeter (pASC) allows measurements over large temperature ranges on milligram-sized samples with high resolution in temperature, enthalpy, and heat capacity. In addition to the heating and cooling modes of the pASC, it can also be used as a classical heat step calorimeter and in differential scanning calorimetry (DSC) type heat-flux or power-compensated modes. As examples, enthalpy results are presented for the melting transitions of gallium and water, and for phase transitions in an aqueous lipid vesicle suspension and in a liquid crystal.